Hema Imager from Hema Imaging is another affordable thermal camera accessory for smartphones and tablets that had launched a Kickstarter crowd-funding campaign a few months ago. Unfortunately even though there were quite a lot of supporters the goal of the campaign has not been reached, but the project is not dead and the people being it are still working on improving things and promise to launch a new crowd-funding campaign soon. Hema-Imager uses a thermal imaging sensor with resolution of 64×62 pixels and connects to mobile devices over a Bluetooth interface, users will have access to three primary image modes – thermal overlay on color camera, thermal overlay on wireframe camera, and raw thermal image. The idea of the device is to be paired with a mobile gadget that already has a visible light camera, so that visible and thermal images can be overlayed, but you should be able to use the thermal images with a computer over WiFi as well if you are Ok with just the thermal images.

hemaimager-specifications-and-features

The most interesting thing about the HemaImager is that the device does not use an uncooled microbolometer as a thermal sensor (like many thermal cameras do, especially in the more affordable range), but instead is relying on a thermopile array as a thermal sensor. This allows the HemaImager to work without the need to recalibrate from time to time in order to avoid the device to start reporting false thermal information. As most thermal imaging devices rely on microbolometer arrays for sensors they need to recalibrate the sensor array from time to time in order to continue reporting accurate temperature data and this means that every few seconds you get a pause in the measuring that the device performs until it recalibrates and is available for use again.

Hema Imager Specifications:
– 64×62 thermopile array with integrated optics
– Best sensor resolution at this price at 0.61 degree angular resolution
– No non-uniformity correction needed with thermopile technology
– Frame rate up to the ITAR-TASS regulations limit of 9 frames per second to any fully Bluetooth or WiFi-capable device.
– Low power consumption and 850 mAhr battery provides up to 8 hours of continuous use without charging, or over a month if just using for 10 minutes daily.
– Android application for smartphone or tablet
– iOS application for iPhone and iPad
– Python & OpenCV application for windows & linux desktop
– App or button-driven laser pointer and online temperature display aligned to center of field of view with 2 deg C accuracy
– Thermal measurement range: -20 degrees Celsius to 232 degrees Celisus

The projected price for the end product should be $250 USD which will make the Hema Imager a really affordable thermal camera accessory for module devices with good features and specifications if/when it becomes available. Since the Kickstarter project did not get funded completely and the people behind the project plan to relaunch a new campaign the device may not see the light of day before sometime in 2015, maybe the second half, you may want to look at some other alternatives that may not be so good and affordable or flexible, but are already available on the market.

Visit the official HemaImager website for more information about the project and for status updates…

ir-blue-accessory

It seems that we have reached a time when users are willing to have more and more functionality available for their smartphones, so it is no wonder that we are seeing more and more interesting accessories. That trend could not pass thermal imaging as well, though since the sensors that are used in thermal cameras are still quite expensive some compromise may be required to make a thermal imaging accessory affordable enough. IR-Blue is one such device and it is even an open source project – an affordable thermal imaging accessory compatible with both iPhone and Android smartphone and tablet devices that can increase the functionality of your mobile device. IR-Blue uses a 64 zone non-contact InfraRed sensor array to read the temperature of what you are viewing and the device connects using Bluetooth to your iPhone or Android device to show the temperature readings as colors on the screen.

ir-blue-accessory-2

The only drawback that the IR-Blue has is that the sensor it uses is very low resolution as compared to what even the more affordable thermal cameras do come equipped with, but still when you overlay the thermal information on top of actual image of the same object in the visible light spectrum the results can be quite interesting and useful. The 64 zone infrared temperature sensor used is essentially a 16×4 pixel device, but it still beats using a non-contact infrared thermometer with a single point of measurement and IR-Blue does come with a better price than a mid or high-end non-contact infrared thermometer and still offers better results.

IR-Blue features and specifications:
– 64 Zone Infrared Temperature sensor
– The sensor is factory calibrated for -20 to 300 ˚C (-4 to 572 ˚F)
– The sensor temperature range is -50 to 300 ˚C
– Sensor Field of View (FOV) 60˚ by 16.4˚
– (NETD) 0.25K rms
– Dual mode Bluetooth 2 and 4 wireless connectivity for Android and iPhone iOS devices.
– PC, Mac or anything that supports Bluetooth can be used with your custom application.
– Uses 4x AAA batteries

The IR-Blue works with iPhone 4S, 5 and 5s/5c, the iPad 3 and newer or the 5th gen iPod Touch. Apple devices need iOS 6 or higher. Android devices need Android OS 2.3 or newer to be compatible. You can get a fully assembled IR-Blue device for $195 USD from the creator of the device RHworkshop in the US or for €199 EURO from their European partner FIR Sensors. It can be a fun extra accessory for your smartphone that will allow you to start exploring the world of infrared thermography before deciding if you should get a more serious and thus more expensive solution for thermal imaging.

thermal-image-iron-palette

We have already talked about what are and how thermal cameras work, but now it is time to do a quick look at what do thermal images look like usually. Thermal cameras do not actually detect color as the infrared range they operate in is way beyond the range of the visible light, instead they record thermal information and that thermal information is then displayed in a way that we can visually interpret it in the form of an image. To make it easier for people to easily analyze a thermal image visually it is represented using a false colors representing the difference in temperature and the most commonly used color palette for that is the so called Iron one (shown above) where black is for the coldest areas, then blue and purple for slightly hotter areas, the mid-range of temperatures is usually red, orange and yellow and then going to white for the hottest parts. These false color visualizations usually do come with a small scale next to the image that show the colors used and what temperature range they cover as otherwise the person seeing a thermal image may get the wrong idea about the actual object temperature. It all depends on the temperature range that has been recorded, so black (the coldest part) on a thermal image can represent 0 degrees Celsius, 23.5 degrees C or another value and the same goes for the hottest and whitest part it could be 62.3 degrees Celsius or 200 degrees C. In thermal images using false colors to represent the difference in temperature there is no specific temperature representing specific color from the color palette used, the colors are just there to make it easy to distinguish the coldest from the hottest parts.

thermal-image-other-color-palettes

Another very common way is to represent a thermal image is in the form of a grayscale image, where you get only black to white colors passing through various levels of gray to represent the difference in temperature. This way of representing thermal images is often used in thermal security cameras or night vision thermal devices, but you will probably see it rarely used in other areas when thermal cameras are needed. The reason for that is, because it is harder for a normal person to distinguish the difference in temperature when only a single color is used and only the level of intensity is varied. It is much easier when you use a color palette with multiple colors. Aside from the most common Iron color palette that we’ve shown to you above here you can see some of the other often used false color representations used for thermal images. These are the Grayscale palette that we’ve already discussed as well as Arctic, Lava and Rainbow, and you may also find a versions of these with higher contrasting color palettes to make differences even more apparent. There of course could be thermal images using different color palettes as well, but as long as you have the smaller scale with the used colors and what temperatures they represent you should be able to quickly get an idea on what you are seeing in terms of temperature. Another interesting way of focusing the viewer’s attention to a specific area of the thermal image is to use grayscale thermal image with color only on specific areas that are either below or above certain temperature or if they fit in a specified thermal range.

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